In the case of alpha decay, it is convenient to consider the alpha particle to be 'pre - formed' in the nucleus prior to emission. What about in beta decay? If we take a simple particle in a box model as a rough approximation, taking the lowest state in the box as n = 1 and assuming a nucleus of mass number 200, the kinetic energy of an pre - formed electron bound inside the nucleus is about 1.5 GeV. What conclusion can you draw from this? What does it imply about considering a pre - formed beta particle inside the nucleus?